Sheet propellant



Dec. 22, 1959 G. SCHECTER ET AL SHEET PROPELLANT Filed Oct. 51, 1956INVENTORS GEORGE SCHECTER WlLLlAM J. KROEGER BY a. QQM Zmm ATTOR N EYs2,918,005 Patented Dec. 22, 1959 2,918,005 SHEET PROPELLANT GeorgeSchecter and William J. Kroeger, Philadelphia,

Pa., assignors to the United States of America as represented by theSecretary of the Army Application October 31, 1956, Serial No. 619,644

4 Claims. (Cl. 102-49) (Granted under Title 35, U.S. Code (1952), see.266) The invention described herein may be manufactured and used by orfor the Government for governmental I purposes without payment of anyroyalty thereon.

This invention relates to a propelling charge for a projectile firedfrom a gun and has for an object to provide a propelling charge in aform suitable for use without the necessity for usual enclosing casebeing present, whereby a substantial saving in weight is made possible.Another object is to provide a propellant capable of giving a closeapproach to uniformity in presfixed ammunition has been customary, asoft metal.

cartridge case being used to house the propellant and secure theprojectile in an end portion of the cartridge case. With the advent ofrecoilless guns of the Kroeger- Musser type disclosed in U.S. Patent2,466,714 dated April 14, 1949, efforts have been made to keep the gunand ammunition as light in weight as is possible for desirableportability in rough terrain. The cartridge case for ammunition for thatgun was made as.light as was reasonably possible. It was made perforatevfor a substantial part of its length for the primary purposeof'allowing the gases to be directed radially. outward and thenrearwardly through the nozzles for overcoming the thrust of recoil. As aresult a considerable reduction in weight of the cartridge case wasefiected. It was realized that the lightest cartridge would be onehaving no propellent case at all. Making the propellant separatelyloaded after the manner of the larger caliber g ls; Was npt feasiblebecause too large a proportionof-the propellant would ,be blownrearwardly and its effectiveness in raising the gas pressurebehind theprojectile lost, t h u s reducing the, effectiveness of the weapon.

According to the propellent case has been eliminated making possible agreat saving in weight of the ammunition that has to be supplied to thegun while at the same time reducing the loss of unburned propellant thatwould otherwise be blown rearwardly.

More specifically, the present propellant is made in sheet form withportions of it connected to reduce the portion of discrete particles ofincompletely burned material being blown rearwardly. Still morespecifically, one connection is the sheet material itself whereby theentire unitary mass is a spirally wound sheet of propellant. Anothertype of connection forming a unit is between discrete layers fittingover a supporting arbor or tube, which may or may not be filled withblack powder or other igniter material and which when so In the smallercaliber guns,

present invention, the weight of the 2 filled will have a number ofperforations through the walls thereof whereby flames of the ignitermaterial will ignite many of the layers.

Fig. l is the top plan view showing a sheet constituting one embodimentof this invention.

Fig. 2 is a section on the line 22 of Fig. 1.

Fig. 3 is an end view of the roll of the sheet material of Figs. 1 and2.

Fig. 4 is a side view of a collection of circular discs cut from thematerial of Figs. 1 and 2 and mounted on a supporting tube. V

Fig. 5 is another collection of circular discs cut from the material ofFigs. 1 and 2 but being of uniform diameter.

Referring to Figs. 1 and 2, a corner of a sheet of propellent material10 is shown as being provided with protuberances 11 formed during theprocess of rolling the material in manufacture. A nominal, though notexact, composition of a typical sheet material is nitrocellulose 55%,nitroglycerine 43%, ethylcentralite 2%,

lamp black 2%, moisture 1%, the total volatiles of the foregoing beingabout 50%. Many other compositions for a sheet propellant will beapparent to those skilled in this art. A typical size for the sheetmaterial of Figs. 1 and 2 is a thickness of .0205 inch for the sheetwith the protuberances rising .013 above the surfaces of the sheet, theprotuberances being .10 inch in diameter, and spaced between the centersabout .375 inch. The geometry of the elements of the sheet propellantcan be varied to suit the ballistic requirements of special weaponsystems.

In Fig. 3, a sheet of the material of Figs. 1' and 2 is shown asrolledinto a spiral roll 12 upon a tube 13 after the manner in whicha carpetis rolled. The supporting tube 13 serves as a structural element of thecartridge and also as an element of the ignition system as is descnbedmore in detail for the embodiments of Figs. 4 and 5. Although theembodiment illustrated in Fig. 3 is not the preferred one, nevertheless'it possesses an advantage in that the spaces between layers due to theprotuberances are effective in providing a path for the ignition gasesto impinge on themajor portion of the ignitable propellent. surfacesthereby facilitating the ignition process and initially directing theproducts of combustion longitudinally of the gun and rearwardly.

In Fig. 4 is shown a large quantity of discs 14 a majority of which areof varying diameters, stamped from the sheet material from Figs. 1 and 2and mounted upon a supporting tube 15 filled with black powder 16, thetube 15 being perforated so that the products of combustion of the blackpowder may radially outwardly move into and ignite the sheet propellant.A special purpose of the embodiment shown in Fig. 4 is the use of thepropellant charge in a recoilless rifle having a central venturiopening, the tapers to the charge being effective in providingincreasing spaces, one directed to-' ward the rear venturi opening andthe other directed in an opposite direction toward the gun barrel butnot shown for the full length. The purpose of the increasing annularareas is to accommodate the increasing flow of gases. The taper forwardand that rearward may or may not be the same. The black powder in thetube 15 is ignited by any appropriate form of primer and the tube 15 mayor may not be secured to a projectile in front of the propelling charge.Where tube 15 is not secured to the projectile, provision must be madefor centrally supporting the end of reduced diameter of the propellingcharge. The size of the charge depends upon the gun in which used, butone size found desirable for a mm. recoilless rifle had the large end3.25 inches in diameter with a half-dozen sheets of the propellant Ethe. left end, the diameter of; the smaller disc was 1.55 I A incheswhile the 'met'al tube--15. was 1.157 inches in the i outside diamet'erfl 'lnasrnuch as each disc has :a 'EhiCk-e i ness of .025inch-F013 inch, the total length f the I tapered discswas 254 ti'mesthis, inasmuch as there were i of the same uniform diameter 17 at theright end; .At

' 2i4 discsin theen'lbodment shoWn.-' i

p In Fig '5, the propellant there illus'tratedis a quantity of discs allof the same diameter 17a mounted upon a I metal or consumable tube a and.filled with black powder 164, the tubefbeing perforated to facilitateignition i 1 of the many sheets mounted thereon. The embodiment i shownin Fig. '5 finds: specialusein the .Kroeger-Musser type recoilles'srifle disclosed in ULS. Patent No; 2,466,714 l 1 I A dated April "14,1949; Thetube. 15a is secured to a projectite 1 18. Propellantisupporting tubes in Figs; 3 and 4 may also'beof consumable material; i i1 i 1 i Among the advantages of the present invention may be lnrent'ionefd the reduction weight of thecart ridg'e because "of theelimination of the cartridge case, this reduction being as much'as aboutto where the standard 'haps this reduction in weight of propellant=ejected may 20%? in the amount of iunburned. propellant which is hejected ream/army through the ventu 'ri openings. :Per- 5 f 1 .3- eihswe s t p pe m c r w d s s e ml in=whiGhsaid-1 y6rs iarecireular; discs,mounted on saide tubular supportsuch that a perpendicular to their;side. j t

=taces is parallel to the longitudinal; axis of. said: tubular i jsupport,- said; tubular support being perforate, and said z layers ofdiscs gradually= reducing in diameter toward 1 l 1 both ends of saidtubular support. a

I be said tolbe duetothefact that the major portion of- 2 ithepropellantbeing of: sheet material is'connected withi i adjacentsheets either through: the supporting tube on 5 lwhich rnountedor asinFig.=3 by the same being a i continuous. sheet ornearly $0.. I Animportant advantageinitheipr'esnt. invention? is "the betterreproducibilityiin' 3 results; due "to-thefi xed 'geo'metryof propellantand the uniform space distribution during ignitiont The emboldh merits;illustrated in Figs. 4fand 5 are preferred'forthe' 'be fin o'rsp'i'nstabilized; Either therollor disc propellant is retained and fixed inposition between and with respect to both aprimer and a projectile. Aflexible, tough, consumable covering that is light in weight andimpervious to moisture should be wrapped around the propelling charge ofthis invention and enable such charge to be fixed, retained, andprotected substantially as 'fully as does the usual metal case yetwithout the usual weight of the metal case. The long taper toward acentral venturi provides increasing space through which the products ofcombustion move rearwardly. In a usual cylindrical propellant chamberafsaving in weight of the gun is possible because the large prior artlongitudinally tapered gas passageways outside the propellant chamber1'10 longer need to be as large with the result a reduction in size orpossibly the elimination of these previous passageways eflects asubstantial reduction in weight of the gun.

We claim:

1. In combination with a projectile, a lightweight propelling charge amajor portion of which needs no of comparison j is T the usual;metalcartridge case for i i e containing a propellant charge; 'Another;advantage of i the present invention is: a reduction of about '15 =tortroe e'emuss'erreturnees tide, and of these,- those illusitratedinFigs; 4 ahd fi are arranged to direct the product's: I otcotnb'ustioninitially radially outward. The cartridge tor-use with either the rollor-disc type propellant may f Jayer, whereby ignition ofsaidiayers-outward-from saidtubular support; p

: 2. A, lightweight propelling charge according to claim 1, 4 4 :iniwhic hsaid layers, are circular discsmounted on said; tubular supportsuch that: a perpendicular to their side faces is parallel to thelongitudinal axis of said tubular support, said-tubular support beingperforate, and. said discs gradually-reducing in {diameter towardoneendiojf said tubular support.

-.rigid case, a rearwardly extending substantially inelastic etubularsupport; filled :withan explosivefor ignition of Zsaid propellingcharge, said propelling charge comprising 1 I p I a-pluralityof layersof sheet propellant, means for mounting; saicl layers of sheetpropellant. on said tubular sup? port passing through said layers tomaintain; substantial; 3 3 i I I uniformity in arrangement with zrespectto each layer i and the longitudinal :axis of. said tubular support,each:

layer of sheet propellant being; solid and :imperforatein; 1 i lplanes-parallel and perpendicularto the longitudinal axis f fOf-Slldtubular support and .radiallybeyond said tubular g a support; each layerof sheet: propellant; having .protuber;

ancesafiixed to at least one face of said layers, said pro' tuber-antes;spacing each layer a uniform distance apart from a contiguous layer, theouter end; surface of; each 1 i I i protuberance; engaging a side;surface: of an: adjacent proceeds radially. e

' 1 4; l h w ht t ave l ha :n si M ni 5 i i p of which is-of a typeineedingnn rigid-case, comprising; I

a plurality sot connected imperforate layers of sheet I propellant,-means for mounting: said. layers on at least: one: substantiallyinelastic support passing through said; g 1

- ay s; chJay r h v pr t r ce pa n ne layer,

i a uniform; distanceiaparttrom a contiguous -layer, where-: e

by products of combustion will be: directed outwardly. a 1

- between unburnedlayer portions, such fixed geometry of arrangement ofpropellant in a gun with respect to surface distribution and withrespect to progress of combustion enables an improved approach touniformity in ballistic reproducibility between successive charges bymaintenance of uniform spacing between said layers during ignition, saidlayers being integrally connected in a single sheet wound in a rollhaving ageneral spiral cross section.

References Cited in the file of this patent UNITED STATES PATENTS989,375 Luciani Apr. 11, 1911 1,274,258 Gerdom July 30, 1918 2,421,522Pope June 3, 1947 2,436,826 Regadet a1. Mar. 2, 1948 2,466,714 KroegerApr. 12, 1949 2,494,562 Kessenich Jan. 17, 1950 FOREIGN PATENTS 207,540Switzerland Feb. 16, 1940

